Influence of chemical and natural cross-linkers on dentin bond strength of self-etching adhesives

Objectives. The objective of this study was to evaluate the effect of chemical collagen cross-linkers on the bond strength of three self-etching adhesives to dentin. Materials and methods. Exposed dentin from the buccal surface of 45 incisors bovine was used to analyze the effect of chemical cross-linkers. The control groups were tested with self-etching adhesives (Clearfil SE Bond, Clearfil SE Protect and One-up Bond F Plus) according to the manufacturer instructions. Two cross-linkers agents were tested: 5% glutaraldehyde and 6.5% proanthocyanidin-rich grape seed extract (both for 10 min). After surface treatments with the agents, the surfaces were washed with distilled water, followed by the bonding/build-up procedures. Restored teeth were prepared for microtensile bond strength test and specimens tested in a universal testing machine (0.5 mm/min) after 24 h storage. Fracture sites of the bonded interface qualitatively evaluated. Results. According to two-way ANOVA and Tukey test (p<0.05) glutaraldehyde pretreatment did not affect the microtensile bond strength of any of two self-etching systems (p>0.05). However, when the grape seed extract was used with Clearfil SE Bond, the dentin bond strength values increased (p<0.05), but decrease for the One-up Bond F Plus treated-group (p<0.05). For the Clearfil SE Protect there was no difference between treatments (p>0.05). Conclusions. The effect of the application of grape seed extract cross-linker was product-dependent and glutaraldehyde did not affect the bond strength to dentin.